Vinyl chloride polymer plasticized with 3, 5, 5-trimethyl-1-hexanol-polybasic acid ester



Patented Sept. 1, 1953 UNITED STATES PATENT OFFICE VINYL CHLORIDEPOLYMER PLASTICIZED WITH 3,5,5 TRIMETHYL 1 HEXANOL- POLYBASIC ACID ESTERWarren L. Beears, Cleveland, Ohio, assignor to The B. F. GoodrichCompany, New York, N. Y., a corporation of New York No Drawing. Originalapplication April 8, 1948, Serial No. 19,897. Divided and thisapplication March, 13, 1951, Serial No. 215,389

6' Claims. 1

This invention relates to plasticized resin compositions and pertainsmore particularly to compositions comprising a polymer of vinyl chlorideplasticized with an ester of 3,5,5-trimethyl hexanol with polybasicacids.

To be useful as a plasticizer, it is desirable that a compound havecertain properties. These properties include: compatability with thematerial to be plasticized; little or no flammability; clarity andalmost complete lack of color; almost completelack of odor and taste;resistance to light, water, chemicals and oils; stability to atmosphericconditions; reluctance to crystallize or CH3 H (CH3 separate frommaterials with which it is incorporated; high melting point andnon-volatil- 2) ity; ability to decrease viscosity of materials withwhich it is incorporated and to impart ductility and tenacity thereto;non-conductivity of electricity; compatability with fillers, dyes andpig ments; ability to produce highly elastic, nonshrinking andnon-scratchable surface; flexibility at high and low temperatures; andstability on aging.

I have now discovered that esters of 3,5,5-trimethyl hexanol withpolybasic acids exhibit the above properties to a remarkable degree andpossess electrical resistivity and resistance to water which areoutstandingly superior to that of other esters of straight or branchedchain higher alcohols such as n-octanol and 2-ethyl hexanol.

The esters of 3,5,5-trimethyl hexanol which are utilized as plasticizersin the compositions of this invention are highly branched and arecharacterized in that each alcohol residue, therein contains a neopentyl(H3C: C--C- cm H grouping, derived from the 3,5,5-trimethyl hexanol,

CH3 H CH3 H H phthalic acid contains two neopentyl groups and has theformula w i i w s w un wa H H H H CH3 H H CH3 H CH3 l I g I I ?Fi I IFOR 10 A H H H H CH3 Similarly, the ester of 3,5,5-trimethyl hexanolwith adipic acid contains two neopentyl groups and has the formula Theester of 3,5,5-trimethyl hexanol with a tribasic acid contains threeneopentyl groups. For example, the ester with phosphoric acid has theformula I BE HOHa 40 though this has not been established withcertainty.

The polybasic acid with which the 3,5,5-trimethyl hexanol is esterifiedmay be either inorganic or organic, aliphatic or aromatic. For

45, example, inorganic acids such as boric acid, phosphoric acid,carbonic acid and the like may be used as may organic polybasic acidsincluding aliphatic polycarboxylic acids such as oxalic acid, malonicvacid, succinic acid, glutaric acid, adipic 5Q acid, pimelic acid,suberic acid, azelaic acid,

brassylic acid, thapsic acid, maleic acid, fumaric acid, glutaconicacid, alpha-butyl-alpha-ethyl glutaric acid, alpha-beta-diethyl succinicacid, 1,1,5-pentanetricarboxylic acid, 1,2,4-hexanetricarboxylic acid,l,2,4-butanetricarboxylic acid; and aromatic polycarboxylic acids suchas phthalic acid, isophthalic acid, terephthalic acid, hemimelliticacid, trimellitic acid, trimesic acid, mellophanic acid, pyromelliticacid, benzenepentacarboxylic acid, naphthalic acid and the like.

The esters described hereinabove may be prepared by reacting thepolybasic acids, or the corresponding acid anhydrides or chlorides, with3,5,5-trimethyl hexanol, or by reacting sodium salts of the acids withchlorides or other halide esters of the alcohol under suitableconditions.

When reacting the alcohol with the acid or its anhydride or chloride, itis desirable that a molar excess of the alcohol be used and preferably aratio of 3 moles of the alcohol to one mole of the acid is used,although the alcohol-acid ratio may be as high as :1 or higher and aslow as 1:1 or even lower.

The reaction temperature is not critical and may be varied widelydepending on the particular ester being prepared. For example, inpreparing the phthalate ester a temperature of from 200 to 240 C. hasbeen found to be optimum. In preparing the phosphate ester the preferredtemperature range is approximately 25 to 50 C. In general, esters of3,5,5-trimethyl hexanol may be prepared at temperatures of from 20 C. orlower to 300 C. or even higher with good results.

The reaction is conducted by adding the anhydride, acid or acid halideto the 3,5,5-trimethyl hexanol which has been cooled to lowtemperatures, preferably below C. After the addition is complete, themixture is brought to the reaction temperature. As the reactionproceeds, monoester is formed which is undesirable from the standpointthat it tends to decompose a part of the polyester and thus decrease theyield of the desired product. Furthermore, due tothe carboxyl groups ofthe monoester present, the acidity of the reaction product is high,resulting in an impure product. It is important, therefore, that themonoester be separated from the reaction mixture or converted to a formin which it has no harmful effect on the reaction. Separation of themonoester may be accomplished by high temperature, high vacuumdistillation. A second method involves the addition of sum cient base toneutralize of the carboxyl groups present, after which the product isdistilled to recover the pure ester of 3,5,5-trimethyl hexanol.

The preferred method consists in adding a finely-divided ion-exchangeresin such as one of the products known commercially as Amberlite to thereaction mixture to remove undesirable monoester. The mixture is thenwashed with an organic solvent to remove the resin-monoestercombination. The desired ester is recovered by distilling off thesolvent preferably at reduced pressures.

The following examples will serve to illustrate the preparation ofesters of 3,5,5-trimethy1 hexanol. There are, of course, many variationsand modifications in the procedure which will be apparent to thoseskilled in the art. All parts are by weight.

EXAMPLE I 35.2 parts (.238 mole) of phthalic anhydride are added slowlyto 100 parts (.694 mole) of 3,5,5-trimethyl hexanol in a glass reactionvessel fitted with an esterification head. After the addition iscomplete the temperature is raised to 200 C. to 240 C. for a period ofsix hours. The excess alcohol is then removed by distillation at apressure of mm. and a temperature of 90 C. The temperature is thenraised and phthalic anhydride removed at from 135 to 190 C. There areobtained 87.5 parts of di-(3,5,5-trimethyl hexyl) phthalate (B. P. 170C./.2 mm., N 1.4819, Sp. (31. 0.9655, viscosity 105.5 cp. at 22 C.,vapor pressure 800 microns at 220 C.)

EXAMPLE II 117 parts of phthalic anhydride are added to 390 parts of3,5,5-trimethyl hexanol in a glasslined reactor equipped with anagitator and a glass-lined column which contains ceramic packing. 231parts of benzene are added to cause initial circulation and the reactionmixture is heated, with 140 p. s. i. of steam on the reactor jacket,

the reaction mixture being agitated constantly. As the benzene boils itentrains from 20 to 30% by volume of the alcohol. At the same time waterformed by the reaction passes with the alcoholbenzene mixture throughthe condenser into a decanter where the water separates from thealcohol-benzene mixture and collects at the bottom of the decanter. Thealcohol-benzene is returned to the reaction mixture, the recirculationrate of the alcohol-benzene mixture being maintained throughout thereaction by the addition of benzene to maintain a constant boiling rateas the amount of unreacted alcohol decreases. The benzene is thenremoved by straight distillation. The excess alcohol is removed by steamdistillation. superheated steam is passed into the bottom of the reactorat a rate sufficient to maintain a pressure difference of about 2 p. s.i. from the reactor to the top of the column. When all excess alcohol isremoved the rate of the stripping steam is increased to maintain apressure difference of about 3 p. s. i. from the reactor to the top ofthe column. The stripping is continued in this manner until the acidnumber of the product reaches a minimum value. 274 parts (90.8%) ofdi-(3,5,5-trimethyl hexyl) phthalate (B. P. 170-175'C./2 mm.) areobtained.

EXAMPLE III 76.7 parts (0.5 mole) of phosphorus oxychloride (B. P. 104C./'760 mm.) are added over a period of 50 minutes to 592 parts (4moles) of 3,5,5-trimethyl hexanol which is maintained at 11 C. duringthe addition period. The reaction mixture is allowed to warm to roomtemperature and is then heated for 2 hours at a temperature of from 25to 50 C. The excess alcohol is then removed by vacuum distillation at apressure of 30 mm. and a temperature of C. and the residue is treatedwith 50% aqueous solution of sodium hydroxide to neutralize the acidformed in the reaction. The product is then distilled at a pressure from.25 mm. to 1 mm. and a temperature of 94 to 168 C. 151 parts (60%) oftri-(3,5,5-trimethyl hexyl) phosphate C./.25 mm.) are obtained.

EXAMPLE IV 153.4 parts (1 mole) of phosphorus oxyohloride are added overa period of 50 minutes to 1152 parts (8 moles) of 3,5,5-trimethy1hexanol which has been cooled to 2 C. The reaction mixture is thenheated at a pressure of 25 mm. and a temperature of 50 C. for a periodof 24 hours. The excess alcohol is then removed by distillation at 150Canal 1 mm. pressure. The residue is treated With 125 parts of'Amberlite IR-4 resin and 125 parts of water to remove acidity present.The ion exchange resin is removed by filtering and the filtrate washedwith hexane after which the hexane layer is separated from the'ester atreduced pressures. 372 parts (74%) of tri-(3,5,5-trimethylhexyl)phosphate (B. P. 165-170 C./.25 mm.)

Similarly, other esters of 3,5,5-trimethyl hexanol are prepared by theabove methods. For

example, di-(3',5,5-trimethyl hexyl) succinate is prepared by reactingsuccinic anhydride with 3,5,5-trimethyl hexanol, and1,2,4-tri-(3,5,5,-trimethyl hexyl) adipate is prepared by reacting.

1,2,4-butane tricarboxylic acid with 3,5,5-trimethyl' hexanol.

As disclosed hereinabove, the esters of 3,5,5-trimethyl hexanol areexcellent plasticizers for rubbers, synthetic resins and especially forpolyvinyl chloride and similar vinyl resins.

Vinyl resins similar to polyvinylchloride include polyvinyl bromideand'copolymers of vinyl chloride or bromide with one or more otherpolymerizable unsaturated compounds containing a single olefinic doublebond such as vinyl acetate, vinylidene chloride, vinylidene bromide,styrene, acrylonitrile, methyl acrylate, ethyl acrylate, methylchloroacrylate, ethyl cyanoacrylate, methyl methacrylate, diethylfumarate, diethyl chloromaleate, isobutyl crotonate, vinyl isobutylether, vinyl methyl ketone, vinyl benzoate, vinyl butyrate, vinylfurane, vinyl pyridine,

dichlorostyrene, isobutylene, ethylene and the like. All such polymericmaterials are polymers of vinyl halides and are effectively plasticizedby the esters of 3,5,5-trimethyl hexanol.

To illustrate the excellent properties of materials plasticized withesters of 3,5,5-trimethyl hexanol, polyvinyl chloride stocks areprepared by admixing parts of powdered polyvinyl chloride and 20 partsof di-(3,5,5-trimethyl hexyl) phthalate in a container to form adoughlike mix. The resin plasticizer mix is then placed on a two-rollmixing mill and the temperature of the mill gradually raised. When thetemperature of the mill reaches 240 F. the plasticizer adds to the resinand, after a few minutes milling, a clear continuous homogeneous sheetof plasticized resin is obtained. The sheet may be cut without tearing aragged edge and is free from nerve, that is, it does not shrink when asection is out, these qualities indicating that the plasticizer isextremely compatible with the resin and that stocks plasticized withdi-(3,5,5-trimethyl hexyl) phthalate may be processed easily attemperatures as low as 240 F. The sheet is then removed from the milland allowed to cool to room temperature, whereupon it is quite soft andflexible and does not feel greasy to the touch (which indicates thatplasticizer has not bled from the resin) even after standing in air fora period of two weeks.

A portion of the sheet thus obtained is molded in a hot cavity for threeminutes at 320 F. to obtain molded samples approximately 0.075 inchthick. One such sample is exposed to ultraviolet light for 48 hours andis found to be substantially unchanged, there being no oxidation of theplasticizer or discoloration of the sample after this treatment. Anothersample is placed in a. circulating air oven for 4 days at 105 C. afterwhich it is still flexible and its loss in weight determined to be nomore than 4.8% based on the stock and no more than 12.03% based on theplasticizer. A third sample was extracted with water for 16 hours andhas a water extraction of only .01%. Still other samples are tested fortensile strength, elongation, resistance to tear and in each case it isfound that the composition is superior to polyvinyl chloridecompositions containing the same percentage of di-2-ethylhexylphthalate, one of the best known plasticizers for'polyvinyl chloride.

.A composition containing the same percentage of di-Z-ethylhexylphthalate prepared in the same way, however, requires a millingtemperature of 250 to 260 F. before forming a homogeneous sheet, itsheat loss in the C. oven after four days is 10% based on the stock and24% based on the plasticizer and it has a water of extraction of 1.5%.

Furthermore, the electrical resistivity of materials plasticized withthe esters of 3,5,5-trimethyl hexanol are markedly superior to thoseplasticized with other well-known plasticizers. To illustrate thissuperiority, two stocks are prepared accordin to the following recipe:

Parts Polyvinyl chloride 48 48 Di 2-eth ylhexyl phthalate 25Di-(3,5,5-trimethyl hexyl) phthalate. 25 Basic lead carbonate 4. 8 4. 8Clay 3. 36 3.36 Carbon black .48 48 tabulated below:

Resistivity in ohm-cm. 10

Stock plastietter Days Aged at C. Di z ethylhexyl Dt-1g3i5i15-trii) me yexy Phthalam Phthalate The following table gives the electricalresistivity when the above recipe is compounded without the carbonblack:

The marked superiority in electrical properties of the esters of3,5,5-trimethyl hexanol over other well-known plasticizers is apparentfrom the above tables. Of special significance is the improvedresistivity of the unaged sample, the phenomenal increase in resistivityof the sample after being aged 1 day, and the fact that the resistivityremains remarkably higher than that of the stock plasticized withdi-2-ethylhexyl phthalate. Thus, it can be seen that esters of3,5,5-trimethyl hexanol are of great value in preparin compositions forinsulating wires which carry an electric current, especially in D. C.communications equipment, and in other applications where high electricresistivity is an important factor.

Furthermore, since the compositions plasticized with the esters of3,5,5-trimethyl hexanol possess excellent processing properties,extremely low heat loss, and resistance to water, such compositions willremain flexible for long periods of time even though subjected toelevated temperatures and all types of weather, and are accordingly veryuseful as jacket or sheathing compositions, molded compositions, and thelike.

While specific embodiments of the invention have been disclosed herein,it is not intended to limit the invention solely thereto, for it isobvious that many modifications including substituting equivalentmaterials and varying the proportions of materials used are within thespirit and scope of the invention as defined in the appended claims.

This application is a division of my copending application Serial No.19,897, filed April 8, 1948 now abandoned.

I claim:

1. A composition of matter comprising a polymer of vinyl chloride, and,as a plasticizer therefor, an ester of 3,5,5-trimethyl-l-hexanol with apolybasic acid selected from the class consisting of boric acid,phosphoric acid, carbonic acid and organic polycarboxylic acids.

2. A composition of matter comprising a polymer of vinyl chloride, and,as a plasticizer therefor, an ester of 3,5,5-trimethy1-l-hexanol with anorganic polycarboxylic acid.

3. A composition of matter comprising a polymer of vinyl chloride, and,as a plasticizer therefor, an ester of 3,5,5-trimethyl-l-hexanol with anorganic aromatic dicarboxylic acid.

4. A composition of matter comprising a polymer of vinyl chloride, and,as a plasticizer therefor, an ester of 3,5,5-trimethy1-l-hexanol with anorganic aliphatic dicarboxylic acid.

5. A composition of matter comprising polyvinyl chloride, and, as aplasticizer therefor, di- (3,5,5-trimethyl hexyl) phthalate.

6. A composition of matter comprising polyvinyl chloride, and, as aplasticizer therefor, tri- 3,5,5-trimethyl hexyl) phosphate.

WARREN L. BEEARS.

Name Date Easton Mar. 22, 1949 Number

1. A COMPOSITION OF MATTER COMPRISING A POLYMER OF VINYL CHLORIDE, AND,AS A PLASTICIZER THEREFOR, AN ESTER OF 3,5,5-TRIMETHYL-1-HEXANOL WITH APOLYBASIC ACID SELECTED FROM THE CLASS CONSISTING OF BORIC ACID,PHOSPHORIC ACID, CARBONIC ACID AND ORGANIC POLYCARBOXYLIC ACIDS.